Concrete has been used in construction for over 2,000 years, perhaps first by the Romans in their aqueducts and roadways. The Romans used a primitive mix for their concrete. Mortar consisted of small gravel and coarse sand mixed together with hot lime and water. They used horse hair, much like polypropylene fibers are used today, to reduce shrinkage. They even unintentionally entrained the air in the mix by adding animal blood. That process created small air bubbles in concrete, making the mix more durable. While the Romans stopped building concrete aqueducts long ago, concrete is used extensively today throughout the building industry, including high-rise building construction.
As a result of functional and aesthetic demands of owners and/or inhabitants that are ever changing and more demanding, new building structures continue to get larger, both in terms of ground area and height. As these structures get larger, so has the recognition of potential damage and destruction that may be caused to them as a result of natural disasters (e.g., earthquakes or wind storms) or man-made disasters (e.g., bombings). Accordingly, building code requirements today are more stringent than ever before. Advances are continually being made in building design, material, and construction methods to keep up with these demands. Despite these advances, costs incurred in constructing high-rise structures continue to escalate.
A feature common to high-rise structures is the interdependency of the outside and interior walls and framework to the structural integrity and stability of the overall building. Namely, the interior walls, vertical columns, vertical beams and/or floor planks of these structures rely, in part, on exterior vertical columns, vertical beams and/or walls for lateral and vertical support, and vice versa. As a result, damage to an exterior wall can threaten the integrity of the entire structure. If, however, the exterior walls are vertically self-supported and the interior framework of the structure is not dependent on the exterior walls for vertical or lateral support, a percussion (e.g., bomb blast, wind gust, etc.) to the exterior of structure will be primarily absorbed by the exterior walls, while the interior framework and walls will be relatively unaffected by the percussion. In that case, although one or more exterior wall may be damaged or destroyed, any damage to the integrity of the internal framework will be minimized.
Another feature common to these structures is the use of steel vertical beams and vertical columns to support not only the lateral loads of exterior walls, but also the vertical loads of the exterior walls. The use of such vertical beams and vertical columns adds greatly to the material and labor cost of construction.
An example of a low-rise structure that utilizes exterior walls that do not rely on interior vertical beams, vertical columns or walls for vertical support is described in U.S. Pat. No. 4,691,490. That patent purports to describe an exterior building wall comprised of vertically self-supporting modular concrete panels that are arranged and stacked together. The wall relies on the adjacent framework for lateral support. However, in the described invention, window or door components may be substituted for the modular concrete panels. No known window or door components, in and of themselves, could support the tons of vertical load support that would be necessary in a vertically self-supporting high-rise wall. Likewise, in the system described in U.S. Pat. No. 4,691,490, the concrete panels described are just that, concrete panels. No reinforcement for the concrete panels beyond the use of self-contained styrofoam battens is described, again evidencing the use of that invention only in low-rise structures. Further, no provision is made for concrete panels that incorporate openings for windows, doors and/or appliances, and/or have portions of the concrete panels that project out or recess in from the support plane of the wall.
Accordingly, there is a need for a high-rise structure whose interior walls and framework are not dependent on exterior walls or framework for lateral or vertical support. Correspondingly, there is a need for a high-rise structure whose exterior walls and framework are not dependent on interior walls or framework for vertical support. There is also a need for such exterior walls that incorporate openings for windows, doors and/or appliances, and/or have portions of the panels that project out or recess in from the support plane of the wall. Correspondingly, there is also a need for a method and materials for constructing such structures.